فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri - Paris Observatory

The central part of the → atom. It is made up of
→ protons and, in most cases,
→ neutrons. The nucleus is surrounded by a swarm of fast-moving
→ electrons. Almost all of the mass (more than 99%) of an atom is
contained in the dense nucleus. The number of protons in the nucleus
(called → atomic number) determines the type of
→ chemical element.
Atoms that differ only in the number of neutrons in their nuclei are called
→ isotopes.